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2016 ATS MT6 Premium
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Discussion Starter #1
Hello Folks,

Been chasing down some intermittent fuel delivery and rough idle gremlins and have circled back to the DI valve coking issue. (I've already replaced the MAF, EVAP solenoid, plugs and coils [all AC Delco, OEM parts])

I've got 122k miles on the clock, with the majority of them (~80%) being highway miles. I drive the snot out of this car with frequent high load/RPM passing, I've been told that high load/hard driving a TGDI motor actually reduces valve coking and that the primary contributor is stop-and-go traffic/city driving.

All that having been said; has anyone had their intake valves cleaned on their LTG? If so would you mind sharing pics, mileage and method of cleaning?

Thanks much!
 

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2014 ATS 2.0T 6spd manual Performance RWD
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At that mileage I would have them scoped and if they need a good cleaning, have them walnut blasted. That or taking them out yourself are really the only way to get them really clean. There is a cleaner made by CRC that you spray into the throttle body iirc, but that is not as thorough.
 

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Discussion Starter #3
At that mileage I would have them scoped and if they need a good cleaning, have them walnut blasted. That or taking them out yourself are really the only way to get them really clean. There is a cleaner made by CRC but that is not as thorough.
Thanks, I'm thinking I'll pull the throttle body and put my scope down the intake (possibly?) to see how bad they are.
 

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I've been told running E85 helps reduce coking. I commonly run 50/50 93/e85.

I'll let you know in another 40k miles!

(I have an E85 sensor and tune... Don't just run E85.)
 

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Cleaning your valves is a great idea at that mileage. Don’t bother with the throttlebody spray crap. That will not do anything except help you waste money on the product. Best is to walnut blast as stated, or DIY with break-clean and wire brushes.
 

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2013 3.6 RWD Premium - 2006 BMW Z4M
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Do you have any issues or notice a reduction in performance or is this only based on mileage? I had a 2006 Audi with a 2.0T and it was known to have valve buildup issues. I got the valves cleaned at 120k miles but it was because it obviously had issues that needed to be fixed. I wouldn't have spent the I think $800 if there wasn't a noticeable problem.
 

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2015 ATS Sedan / 2.0T / RWD / 6-AT
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Thanks, I'm thinking I'll pull the throttle body and put my scope down the intake (possibly?) to see how bad they are.
Would you like to share the recordings? That is what I have never seen until now. Everybody is talking about cleaners, catch cans, fuel setpup, good oil ... but I miss a before / after comparison.

And youtube is full of Volkswagen, but no GM LTG :D
 

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You may notice some changes like slight decrease in mpg or power but it won’t be terribly obvious unless it is very bad, qt which point you should get them cleaned. $800 for that service sounds a bit steep.

Do you have any issues or notice a reduction in performance or is this only based on mileage? I had a 2006 Audi with a 2.0T and it was known to have valve buildup issues. I got the valves cleaned at 120k miles but it was because it obviously had issues that needed to be fixed. I wouldn't have spent the I think $800 if there wasn't a noticeable problem.
 
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